Bipolar semiconductor devices suitable for use as power switches, such as insulated-gate bipolar transistors (IGBTs), for example, may be implemented in a variety of applications. For instance, IGBTs may be used as power switches in motor drive inverters, as well as in direct-current (DC) to DC power converters. In these and other power applications, on-state voltage drop (VON), turn-off losses (EOFF), and turn-off delay time (Td,OFF) are important operating parameters.
However, conventional techniques for producing desirable on-state characteristics, such as low VON, can undesirably result in increased EOFF and longer Td,OFF. As switching speed increases, switching losses, including EOFF, typically represent a significant portion of total power loss by a bipolar power switch. Consequently, IGBTs and other bipolar switching devices having desirable on-state characteristics and reduced EOFF and Td,OFF during fast switching are highly sought after in the art.